1. Field of the Invention
The invention relates to a combination valve. Furthermore, the invention relates to the use of the combination valve. Specifically, the invention relates to an exhaust-gas recirculation valve in motor vehicles.
2. Prior Art
Valves for gases are known. EP 1 335 158 B1 describes a flap valve for fuel assemblies. The flap valve has a gas inlet and two gas outlets. Each gas outlet can be closed with a valve flap, both valve flaps being arranged perpendicularly with respect to one another. It is possible as a result to guide the entire quantity of gas either through one gas outlet or through the other gas outlet. As a rule, two gas outlets are provided to optionally cool the gas behind the respective gas outlet or to forward it uncooled. The respective switchover then takes place via the valve flaps which are jointly mounted rotatably on a shaft. It is disadvantageous in flap valves of this type that only two settings, which are independent of the gas quantity, can be performed. The entire gas quantity is either cooled behind the respective gas outlet or the entire gas quantity is forwarded uncooled behind the respective gas outlet of the flap valve. Additional regulation of the gas quantity at the respective setting is not possible by way of the flap valves according to the prior art. If the gas quantity has to be additionally regulated according to the operating state, it is necessary to provide in each case shut-off elements in front of or behind the two gas outlets of the flap valve, which shut-off elements can therefore perform a quantitative regulation. The high structural outlay is very disadvantageous here.
DE 34 20 474 A1 has discloses a combination valve having a cylindrical hole and a rotary slide, while GB 1,191,651 discloses a combination valve for a heating system, which combination valve guides a part flow of a heating liquid through a radiator in a regulated manner.